Railway signaling system.



L. A. HAWKINS. RAILWAY SIGNALING SYSTEM. APPLICATION FILED NOV. 8, 1911.

1, 126 ,206, Patented Jan. 26, 1915.

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Inventor:

Witnesses:

, Hawkms,

His fittorneg.

THE NDRRIS PETERS co. PHOTO-LITHQ, WASHINGION. D. c-

L. A. HAWKINS. RAILWAY SIGNALING SYSTEM. APPLICATION FILED NOV. 8, 1911.

1,1 26,206. Patented Jan. 26, 1915.

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Witnesses: Inventor:

Laurece 7T. Hawkins A THE NORRIS PETERS c0. PHOTO-LITHQ, WASHINGTON. DC.

STATES PATENT OFFICE.

LAURENCE A. HAWKINS, OF SCI-IENECTADY, NEW YORK, ASSIGNOR, BY MESNEASSIGN- MENTS, TO THE UNION SWITCH AND SIGNAL COMPANY, A CORPORATION OFPENN- SYLVANIA.

Application filed November 8, 1911.

To all whom it may concern:

Be it known that I, LAURENCE A. HAW- KINS, a citizen of the UnitedStates, residing at Schenectady, in the county of Schenectady and Stateof New York, have invented certain new and useful Improvements inRailway Signaling Systems, of which the following is a specification.

My invention relates to electric signaling systems of the normal dangertype, and particularly to signaling systems of this type in which thesignals are controlled by alternating current and its object is toreduce to a minimum the number of line wires for the proper control ofthe signals.

1 will describe two forms of signaling system embodying my invention andthen pointout the novel features thereof in claims.

In the accompanying drawings, Figure 1 is a diagrammatic view showingone form of signaling system embodying my invention. Figs. '2, 8 and Aare vector diagrams showing the phase relations in certain of the relaysof Fig. 1. Fig. 5 is a diagrammatic view showing a modification of thesignaling system shown in Fig. 1 and embodying my invention. Figs. 6, 7and 8 are vector diagrams showing the phase relations in certain of therelays of Fig. 5.

Similar reference characters refer to similar parts in each of theseveral views.

In the accompanying drawings 1 have shown my invention applied to homeand distant systems of signaling, that is, to systems in which thesignals are adapted to indicate danger, caution and clear, although itsapplicability is not limited to systems of this character. As here shownthe signals are of the one-arm three-position type but it is understoodthat any type of signal adapted to give the three indications may beemployed equally well.

In normal danger signaling systems, as is well understood, the signalsare usually in the danger position of indication, and are moved to theclear and caution position only when they are approached by a car ortrain provided no car or train is within the territory governed by suchsignals and when the car or train passes the signals they are returnedto their danger position.

One feature of a signaling system embodying my invention is theprovision of a line relay of the two-winding type for each Specificationof Letters Patent.

Patented J an. 26, 1915.

Serial No. 659,126;

block section for the control of the signal or signals governing thatblock section, the windings of these relays being supplied with currentsof such relative phases that the signal for the block section directlyin advance of a car or train will be moved to clear position and thesignal for the second block section in advance of the car or train willbe moved to the caution position, and that the signals for thesucceeding block sections will not be affected by such car or train.

Referring now to Figs. 1 and 5 of the accompanying drawings, I haveshown in each view a portion of a railway divided into block sections,10, 11, 12, etc., which blocksections are governed respectively bysignals S, S S", etc. As here shown, these signals are controlled bytrack circuits arranged in accordance with the system disclosed in mycopending application, Serial No. 511,663 filed August 7, 1909. In thissystem each track circuit includes two track relays, A, B, A, B, etc.,for the control of the caution. and clear positions of the signal forthe corresponding block section. Each of these track relays comprisestwo windings one of which is connected with the track rails and theother with an independent source of current. Each track circuit issupplied with alternating signaling current from a transformer l t, 15or 16, etc., the secondary of which is connected with the track railsand the primary of which may be connected with either of two sources ofcurrent ditfering in phase by approximately 90. One or the other ofthese sources is connected with the transformer of a block section bymeans of a circuit con troller D, D, etc., operated by the signal forthe next succeeding block section, the arrangement being such that whena signal is in the danger position, currents of one phase will besupplied to the preceding track circuit, and when the signal is in thecaution and clear positions, current of the other phase will be suppliedto the preceding track circuit. The line windings of each pair of trackrelays A, 13, etc., are connected with sources of current differing byapproximately 90 in phase, and the relation of the phases in these linewindings to the phases supplied to the track circuit is such that whenthe next succeeding signal is in the danger position, relay A will beenergized and relay B de'e nergized; and when the next succeeding signalis in the caution or clear position, both relays A and B will beenergized. As here shown, I obtain the two phases differing by 90 from athree phase transmission line 17 by the use of transformers T, T, etc.,connected in the well known three-phase two phase arrangement.

The explanation thus far given applies to both Figs. 1 and 5, and theportion of each of these systems thus far explained is similar to thenormal clear system disclosed in my copending application Serial No.511,663 herein before mentioned, hence no further explanation of thisportion of either system is necessary.

Referring now to Fig. 1, I will explain the means herein shown forobtaining the normal danger feature of control. In this View, in each ofthe transformers T, T, etc, I have shown a connection leading from themiddle points of the secondaries, which connections are connected withthe common wire 0. By this arrangement of connections I obtain from eachtransformer four phases differing by 90. In the case of transformers T,T and T all four phases are not used, hence the terminals which are notemployed are left disconnected.

For each block section I provide a line relay R, R, R etc., of thetwo-winding type each of which relays controls the operating circuit ofthe signal mechanism for the corresponding block section. For example,the circuit for the caution position of signal S may be traced asfollows from the left hand terminal of transformer T through wire 22,armature 21 of relay R, wire 23, front contacts and armature of trackrelay A, wire 24:, signal S, wires 25 and 26 to the middle point oftransformer T; for the clear position of this signal the circuit is thesame as just traced to the armature of relay A, then through armature oftrack relay B, wire 27, signal S to wires 25 and 26 and transformer T.It will be seen therefore that when relay R is open, signal S isnecessarily in the danger position, and that when relay R is closed,signal S may be in danger, caution or clear position depending on trackrelays A and B.

As here shown the relays R, R, etc., are of the well-known polvphaseinduction motor type, although I do not wish to limit mvself to thisspecific type of relay, for any form of relay having two windingscooperating to close the contacts mav be einploved.

Each relay R, R, etc., comprises two field windings 18 and 19, thesewindings being so arranged with relation to the stator of the relay thatwhen the current in winding 19 leads the current in winding 18 the relaywill be operated to close its armature contacts, but when the current inwinding 18 leads that in winding 19 the armature contacts of the relaywill be open or the relay will be given a reverse torque to hold thesecontacts open. Winding 19 of each relay R, R, etc., is connected withthe adjacent transformer T, T, etc, the connections being so arrangedthat the currents in these windings differ progressively by 90; that is,assuming the phase in winding 19 of relay R to be 0, the phase in thecorresponding winding of relay R is 90, that in relay R is 180, in relayR 270, and so on. This is clearly represented in the vector diagramsFigs. 2, 3 and at, in which the lower vectors refer to the current andvoltage in winding 19 of the corresponding relay, and the upper vectorsrefer to the current and voltage in winding 18 of the correspondingrelay. An inspection of these vector diagrams will show that thereactance of the circuit of winding 18 of each relay is relatively high,giving a large angle of lag of the current behind the voltage; and thatthe reactance of the circuit of winding 19 of each relay is relativelylow because of the non-inductive resistance 33 in series with thewinding 19, giving a small angle of lag of the current behind thevoltage.

The winding 18 of each relav may be connected with the transformer T, T,etc., for the block section in the rear, the circuit including the backcontacts of relay A for such block section in the rear, a reactance 31,which helps to give the current a large angle of lag, and a line wire 28extending throughout the block section. For example, the circuit forwinding 18 of relay R when energized by transformer T is as follows fromthe left hand terminal of transformer T through wires 32 and 31, backcontacts of armature of relav A. reactance 34, wire 28, winding 18 ofrelay R, wire 29 to common wire 0 and middle of transformer T. For eachsignal I provide a circuit controller C, C, etc., operated by the signalin such man ner that the circuit controller is open when the signal isin the danger position and closed when the signal is in either thecaution or clear position. For each block section I provide contacts andconductors adapted to connect line wire 28 extending through suchsection with line wire 28 extending through the block section in therear; for example, the line wire 28 of block section 10 may be connectedwith line wire 28 of block section 11 by means of the following contactsand conductors :Circuit controller C. wire 30, armature 20 of relay R.It will be seen therefore that the current from transformer T may alsopass through winding 18 of relays R and R provided signals S and S arein the cantion or clear positions and relays R and R are closed./Vindings 18 of relays R, R, etc., are so connected with thetransformers T, T, etc., that when these windings are each connectedwith the transformer for the block section immediately in the rear thephase of the currents in these windings differs progressively by thatis, assuming the phase of the current in winding 18 of relay R to be 0,that in winding 18 of relay R is 90, in relay R is 180, etc.

The operation of the system shown in Fig. 1 may now be explained asfollows When a car or train WV enters block section 10 as indicated,track relays A and B will both be opened, so that signal S indicatesdanger. The back contacts of relay A will close the circuit betweenwinding 18 of relay R and transformer T as hereinbefore described. Thephase relations in the windings of relay R will then be as indicated inFig. 4%, from which it will be seen that the current in winding 19 (Cleads that in winding 18, (C and this relay, therefore remains closed,it having been closed when the car or train TV enters the block sectionin the rear of block section 10, for reasons which will hereinafterappear. Track relay A was already closed and track relay B was open, sothat signal S therefore was in caution position. Circuit controller C istherefore closed, so that line wire 28 of block section 10 is connectedwith wire 28 of section 11. Winding 18 of relay R is thereby energizedfrom transformer T, the phase of the current and voltage being the sameas those in the corresponding winding of the relay R, as indicated bythe vector diagram in Fig. 3. The phase of the current in winding 19 ofrelay R is as indicated by C in Fig. 3, and since this current is aheadof the current in winding 18, relay R is energized to close itscontacts. Track relay A being closed and track relay B open, signal Sthen moves to the caution position and in so doing it operates circuitcontroller D to shift the phase of the current in the track circuit ofblock section 11 so that track relay B will be energized to close itscontacts. Signal S therefore moves to the clear position, and the partsof the system will then be as shown in Fig. 1. When relay R wasenergized, and signal S moved to the caution position, winding 18 ofrelay R was connected with transformer T through circuit controllerarmature 20 of relay R etc., the phase of the voltage and current inthis winding being as indicated in the upper portion of Fig. 2. But thephase of the current in winding 19 of this relay is as indicated by C inFig. 2, being therefore approximately 225 ahead of the current inwinding 18, and since thesine of 225 is the same as the negative of sine135, it will be evident that the current in winding 19 lags behind thatin winding 18 by approximately 135 and relay R will have a reversetorque tending to hold its armature contacts open. Hence signal Sremains in the danger position. Nhen the train W advances into blocksection 11, winding 18 of relay R will receive current from transformerT, which current is 90 in advance of that supplied to it by transformerT, hence the current in winding 19 will then lead that in winding 18 andrelay R will therefore be energized to close its contacts therebyclosing the caution position circuit for signal S.

From the foregoing explanation of the system shown in Fig. 1, it will beseen that the essential feature of this system is the provision of arelay for each block section, each of which relays is so constructed andconnected as to respond to current from the first and second blocksections in the rear to close its contacts, but not to respond tocurrent from the third block section in the rear. Hence I obtain theclearing of the signals two blocks in advance of a train but no further.I have also shown in Fig. 1 how the signal lamps may be controlled sothat they will always be lighted when a train is approaching a signalbut cut out at other times so as to save current and prolong the life ofthe lamp. The lamps are indicated at L, L, etc. The circuit of a lamp,for instance, that of lamp L of signal S, is from left hand terminal oftransformer T, wire 22, contact 21 of relay R, lamp L, wires 25 and 26to common wire 0. Thus the lamp L is lighted when relay R is energizedand not otherwise, and, as I have shown, relay R will always beenergized when there is a train in block section 10, or in the sectionin the rear of block section 10. Thus, without additional line wires,the lamps are controlled so as always to be lighted when a train isapproaching, and only then.

In the modification of my invention shown in Fig. 5, I employ a simplerarrangement of transformer connections, but two relays for each blocksection to control the clearing of the signals-a single phase relay, P,P, etc., and a polyphase relay R,

R, etc. The operating circuit for each signal is controlled directly bythe single phase relay P, P, etc., of the corresponding block section.The polyphase relay R, R, etc., of each block section is employed onlyto con nect the line wire 28 extending through its block section withthe line wire 28 of the block section in the rear, as in the system ofFig. 1. Each of these polyphase relays is, as here shown, of theinduction motor type comprising two field windings 18 and 19 the powerfactors of whose circuits are substanti ally equal so that the angle oflag be tween the voltage and the current will be substantially the samein each winding. Winding 19 of each polyphase relay is connected withthe transformer T, T etc. of the corresponding block section in suchmanner that the phase of the current in these windings of adjacentrelays differs by 90. Thus, winding 19 of relay R is connected with theleft hand terminal of transformer T, winding 19 of relay R with theright hand terminal of transformer T, winding 19 of relay R with theleft hand terminal of transformer T and so on. This phase variation isrepresented diagrammatically by the lower vectors in the vector diagramsFigs. 6, 7 and 8. Winding 18 of each polyphase relay is connected inparallel with the winding of the single phase relay P, P, etc., of thecorresponding block section. As in the system of Fig. 1, a line wire 28extends througheach block section; the rear end of each line wire isconnected with the transformer T, T etc. of the corresponding sectionthrough the back contacts of track relay A, A, etc., and the other endof each line wire 28 is connected with the single phase relay and withwinding 18 of the polyphase relay for the next succeeding block section.Each line wire 28 will be connected with the line wire 28 of the blocksection in the rear when the signal for the corresponding block sectionis in caution or clear position and when the polyphase relay R, R, etc.,of the corresponding section is energized, the connection between thetwo line wires including circuit controller C, C, etc., wire 30 andarmature 20 of the polyphase relay. The connections of the line wires 28to the transformers (through the back contacts of relays A, A, etc.) arealternately arranged, so that the phase of the current in the line wiresof adjacent block sections, when the line wires are connected with thetransformers of their own block sections, differs by 90. Thus wire 28extending through block section 10 is connected with the left handterminal of transformer T, and wire 28 of block section 11 is connectedwith the right hand terminal of transformer T. Hence the phase of thecurrents in relays P, P, etc., and in windings 18 of relays R, R, etc.,for adjacent blocks differ by 90 when the line wires which supply thesewindings are connected directly with the transformers for the blocksections in the rear respectively. Winding 19 of the polyphase relay foreach block section is connected with the phase opposite to that inwinding 18 of the same relay when the line wire 28 which supplies suchwinding 18 is energized from the transformer for the block section inthe rear. 'It will now be clear that when the line wire 28 of a blocksection is connected with its transformer by the hack contacts of relayA of that block sect on, the two windings 18 and 19 of the polvphaserelay for the block section next in advance will be energized withcurrents differing by 90 in phase, hence this relay will be energized toclose its contacts; and if the last mentioned line wire is thenconnected with the next succeeding line wire 28, the windings 18 and 19of the relay for the second block section in advance will be energizedwith currents of substantially the same phase, hence no torque will beexerted upon the rotor of this relay and its contacts will remain open.

The operation of the system shown in Fig. 5 may now be explained asfollows When the block section in the rear of block section 10 isoccupied by a car or train W, relay P is closed, and track relay A isclosed and track relay B is open so signal S indicates caution. Whenthis car or train l/V enters block section 10 as indicated in thedrawing, it opens track relay A, thereby connecting line wire 28 forthis block with transformer T. l/Vinding 18 of relay, R is now energizedfrom transformer T, the phase of the current in this winding being asindicate by C in Fig. 7; but winding 19 of this relay is alreadyenergized by current of the phase indicated by C in Fig. 7. Hence relayR is energized to close its armature contacts 20. Circuit controller Cbeing closed, and line wire 28 of block section 10 is thereforeconnected with wire 28 of section 11 through circuit controller C. wire30 and armature 20 of relay R. Relay P is therefore energized, and theclosing of its contacts causes signal S to more to caution position.W'inding 18 of relay R is also energized with current of the same phaseas that in the corresponding winding of relay R, as indicated by C inFig. 6, but this phase is substantially the same as the phase of thecurrent in winding 19 (indicated by C in Fig. 6) hence relay R willremain open, and line wire 28 will not be connected with wire 28 ofblock section 12. The signals for the succeeding block sections willtherefore not be affected. The movement of signal S to caution positionoperates circuit controller D to shift the phase of the current in thetrack circuit of block section 11 so that track relay B closes, causingsignal S to move to clear position. When the car or train XV advancesinto block section 11, it will cause track relay A to connect the linewire 28 of this section with transformer T. The currents in windings 18and 19 of relay R will then be displaced 90 in phase so that this relaywill be energized to close its contacts. The remainder of the operationswill be the same as hereinbefore explained.

The main purpose of reactance 34 shown in both Figs. 1 and 5 is toprevent a momentary short circuit when a train enters an unoccupiedblock. For instance, in Fig. 5, when the car or train W first entersblock section 11, relay A will be deenergized and close its backcontacts an instance before signal S has time to open contact C andbefore relay A can pick up and deenergize Winding 18 of relay R. Thusfor an instant the following circuit is closed,from right hand terminalof transformer T, back contacts of relay A, react-ance 34, contacts 20of relay R, wire 30, contact C of signal S, wire 28 of block section 10,reactance 34: at the entrance of block section 10, back contacts ofrelay A, to left hand terminal of transformer T. Because of thereactance 34 this circuit has no effect, but if the reactances 34 wereomitted this circuit would shortcircuit transformers T and T on eachother during the short time required for signal S to drop far enough toopen contact G or for relay A to pick up. As soon as contact C or theback contacts of relay A open, transformer T is disconnected from, andtransformer T is left connected to, line Wire 28 of block section 11, sothat by the operations just described the circuit of relay P when thecar enters block section 11, is simply transferred from transformer T totransformer T without being opened, and without relay I? beingdeenergized, even momentarily, so that no slow acting devices of anykind are needed to prevent signal S from dropping from caution duringthe above described changes of connections. The same remarks(substituting R for P apply to Fig. 1.

Although I have herein shown only two forms of railway signaling systemsembodying my invention, it is understood that various changes andmodifications may be made therein within the scope of the appendedclaims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is 1. In a railwaysignaling system, a plurality of block sections, a signal for each blocksection, a line circuit for each block section, means in each blocksection controlled by the presence and absence of a car in the blocksection for supplying alternating current to the line circuit of theblock section, the currents thus supplied to the several line circuitsof any three successive sections being of different phases, signalcontrolling apparatus for each signal said apparatus being connectedwith the line circuit for the block section in the rear, contacts andconductors controlled by each signal controlling apparatus forconnecting the line circuit of the corresponding block section with theline circuit of the block section in the rear, the signal controllingapparatus for each block section being responsive in its control of itssignal to current of the phase supplied tothe line circuits of the firstand second block sections in the rear,

and not of the third block section in the rear.

2. In a railway signaling system, a plurality of block sections, asignal for each block section, a source of polyphase signaling currentfor each block section, a line circuit for each block section, means ineach block section controlled by the presence and absence of a car inthe. block section for connecting the line circuit of the block sectionwith a phase of the source of current for the same block section, thecurrents thus supplied to the several line circuits any of threesuccessive sections being of different phases, a polyphase relay for thecontrol of each signal each comprising two windings one of which isconnected with a phase of the source of current for the correspondingblock section and the other with the line circuit for the block sectionin the rear contacts and connections controlled by each polyphase relayfor connecting the line circuit of the corresponding block section withthe line circuit of the block section in the rear, each polyphase relaybeing responsive in its control of its signal and of its said contactsto current in its line circuit winding of the phase supplied to the linecircuit of the first and second block sections in the rear but not ofthe third block section in the rear.

3. In a railway signaling system, a plurality of block sections, asignal for each block section, a line circuit for each block section,means in each block section controlled by the presence and absence of acar in the block section for supplying alternating current to the linecircuit of the block section, the currents thus supplied to the severalline circuits of any three successive sections being of differentphases. means for connecting the line circuit of each block section withthe line circuit of the block section in the rear, and signalcontrolling apparatus for each signal connected with the line circuitfor the block section in the rear and responsive in, its control of itssignal to current of the phase supplied to the line circuit of the firstand second block sections in the rear and not of the third block sectionin the rear.

4. In a railway signaling system, a plurality of block sections, asignal for each section, signal-controlling apparatus for each blocksection for the control of the signal thereof, means for each blocksection for supplying a plurality of signaling currents differing incharacter, a line circuit for each block section connected with thesignal-com trolling apparatus of the next block section in advance,means controlled by the presence and absence of a train in each blocksection for connecting the line circuit of such block section with asource of, current of one character for the block section, the currentsthus supplied to the several line circuits of any three successivesections differing in character, and means for connecting the linecircuits of adjacent block sections together, the signalcontrolling-apparatus of each block section being adapted to respond inits control of its signal to current of the characters supplied to theline circuits of the two block sections in the rear but not of the thirdblock section in the rear.

5. In a railway signaling system, a plurality of block sections, asignal for each block section, signal controlling apparatus for eachblock section, a line circuit for each block section connected with thesignalcontrolling apparatus for the next block section in advance, meansfor connecting the line circuits of adjacent sections together, andmeans controlled by the presence and absence of a train in each blocksection for supplying alternating current to the line. circuit of suchblock section, the currents thus supplied to the several line circuitsof any three successive sections differing in character, thesignal-controlling apparatus for each block section being adapted torespond in its control of its signal to current from the two blocksections in the rear and not from the third block section in the rear.

6. In a railway signaling system, a plurality of block sections, a linecircuit for each block section, means controlled by the presence andabsence of a car in each block section for supplying alternating currentto the line circuit of the block section, the currents thus supplied tothe line circuits of adjacent sections being of different phases, relayshaving windings connected to said line circuits, said relays beingresponsive or not to current in such circuits according to the phase ofsuch current, means including contacts controlled by said relays forconnecting the line circuits of adjacent block sections together, andsignals for the block section controlled by said line circuits,

7. In a railway signaling system, a plurality of block sections, asource of polyphasesignaling current for each block section, a linecircuit for each block section, means controlled by the presence andabsence of a car in each block section for connecting the line circuitof the block section with a phase of the source of current for the sameblock section, the currents thus supplied to the line circuits ofadjacent sections being of different phases, a relay for each blocksection having two cocperating windings, one connected to the linecircuit of the section in the rear and the other in a local circuit, thecurrents in said local circuits of the relays for adjacent blocksections being of differentphase, and means including contactscontrolled by said relays for connecting the line circuits of adjacentblock sections together, and signals for the block sections controlledby the line circuits.

8. In a railway signaling system, a plurality of block sections, asignal for each block section, a line circuit for each block section,means controlled by the presence and absence of a car in each blocksection for supplying alternating current to the line circuit of theblock section, the currents thus supplied to the line circuits ofadjacent sections being of different phases, signal controllingapparatus for each signal, said apparatus being connected to the linecircuit for the block section in the rear and being responsive or notresponsive to current in such circuit according to the phase of suchcurrent, and contacts and connections controlled by each signalcontrolling apparatus for connecting the line circuit of thecorresponding block section with the line circuit of the block sectionin the rear.

9. In railway signaling, a plurality of block sections, a line circuitfor each section, means controlled by the presence of a train in eachsection for supplying alternating current to the line circuit for suchsection, the currents thus supplied to the line circuits of adjacentsections differing in phase, translating means for each sectionconnected with the line circuit for the section in the rear, thetranslating means for each section being affected in one way or anotheraccording to the phase of the current which reaches it, means includingcontacts of the translating means for connecting the line circuits ofadjacent block sections when the translating means is affected in oneway, and signals for the sections controlled by said translating means.

10. In a railway signaling system, a plurality of block sections, a linecircuit for each section, means for each section controlled by thepresence of a car or train in the section for supplying alternatingcurrent to the line m circuit for the section, the currents thussupplied to the line circuits for adjacent sections difi'ering incharacter, signal-controlling apparatus for each section connected withthe line circuit for the section inthe rear and responsive or not to thecurrent in such circuit according to the character of such current,means controlled by the signal-controlling apparatus for each sectionfor connecting the line circuit for the section with the line circuitfor the section in the rear, and signals for the sections controlled bysaid signal-controlling apparatus.

11.- In a railway signaling system, a plurai-l-ityof-blook sections; aline circuit for each section, means for each section controlled by thepresence of a car or train in the section for supplying alternatingcurrent to the line circuit for the section, the currents thus suppliedto the line circuits for adjacent sections difiering in character,translating means tor each section connected With the line circuit forthe section in the rear and afi'ected in one Way or another according tothe character of the cur rent in such circuit, means controlled by thetranslating means for each section for connecting the line circuit forthe section with the line circuit for the section in the rear When thetranslating means is affected in one Way, and signals for the sectionscontrolled by said translating means.

In testimony whereof I afiix my signature in presence of tWo Witnesses.

LAURENCE A. HAlVKINS.

lVitnesses:

BENJAMIN B. HULL, HELEN Onronn.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents,

Washington, D. C.

